Centrifugal casting machine

ABSTRACT

A centrifugal casting machine utilizes permanent molds. Lower mold parts are mounted on a powered turntable, and upper mold parts are mounted on a member rotatable about the retainer of a thrust bearing, beneath a beam spanning the turntable. The beam is drawn downward by a pair of actuators, to close the molds. Openings in the beam, bearing, and suspended member, all aligned with the turntable axis, permit pouring the molten metal while the turntable is rotating, to be forced outward by centrifugal pressure and fill the mold parts held sealed by thrust of the beam exerted through the bearing. To remove a casting, the turntable is latched in a predetermined angular position and the actuators raise the beam which hooks and lifts up on larger radius edge portions of the upper mold part mounting member, detaining it in angular alignment. When the beam reaches its uppermost position, an ejection plate, mounted on the turntable beneath the lower mold parts is lifted to eject a casting. The upper mold part mounting member may be removed downward from the bearing retainer to change such mold parts, by manually turning it until its larger radius edge portions clear the hooks beneath the beam.

United States Patent Muench 1 Mar. 28, 1972 [54] CENTRIFUGAL CASTING MACHINE [72] Inventor: Charles A. Muench, Chesterfield, Mo.

[73] Assignee: Forecast, Inc., St. Louis, Mo.

[22] Filed: Feb. 12, 1970 211 Appl. No.: 10,809

Primary Examiner-Robert D. Baldwin Assistant Examiner-V. Rising Attorney-Jerome A. Gross [57] ABSTRACT A centrifugal casting machine utilizes permanent molds. Lower mold parts are mounted on a powered turntable, and upper mold parts are mounted on a member rotatable about the retainer of a thrust bearing, beneath a beam spanning the turntable. The beam is drawn downward by a pair of actuators, to close the molds. Openings in the beam, bearing, and suspended member, all aligned with the turntable axis, permit pouring the molten metal while the turntable is rotating, to be forced outward by centrifugal pressure and fill the mold parts held sealed by thrust of the beam exerted through the bearing. To remove a casting, the turntable is latched in a predetermined angular position and the actuators raise the beam which hooks and lifts up on larger radius edge portions of the upper mold part mounting member, detaining it in angular alignment. When the beam reaches its uppermost position, an ejection plate, mounted on the turntable beneath the lower mold parts is lifted to eject a casting. The upper mold part mounting member may be removed downward from the bearing retainer to change such mold parts, by manually turning it until its larger radius edge portions clear the hooks beneath the beam.

15 Claims, 4 Drawing Figures BACKGROUND OF THE INVENTION This invention relates to centrifugal casting machines, and particularly to a centrifugal casting machine adapted to utilize permanent molds.

For the production of metal castings to close tolerances, die casting machines are ordinarily used. It has generally been assumed that the centrifugal casting process is useful principally with sand molds; and no general purpose centrifugal casting machines have, to the knowledge of applicant, heretofore been used.

A potential advantage of centrifugal casting is that the centrifugal force generated on rotation presses the molten metal radially outward with great force, filling the molds tightly and driving any gases radially inward. An accompanying disadvantage is that such pressure requires a tight sealed fit between the mating parts of pennanent molds, otherwise some of the molten metal may escape or at least penetrate between the mold parts and form excessive amounts of flash. The problems of holding production mold halves sealedly together during rotation, and yet separating them quickly after a casting is rotated, have heretofore been serious obstacles to the use of such machines.

SUMMARY OF THE INVENTION A principal purpose of the present invention is to hold upper mold parts sealedly against lower mold parts by downward thrust, while the mold parts are being rotated, and to maintain them precisely sealed at all angular positions during rotation. A further purpose is to retain the upper mold parts in angular alignment with the lower mold parts as they are separated vertically so that thy may be again mated and a subsequent casting operation may be begun without taking any new steps to re-align them. Another purpose is to provide for ejection means to strip a casting from the mold part automatically. A still further purpose is to provide, in a preferred form of the invention, pennanent core parts to mate with the other mold parts and yet be easily withdrawn after casting. Additional purposes will be apparent from the detailed specification which follows.

Generally summarizing, the centrifugal casting machine of the present invention has a lower turntable powered to rotate about a vertical axis, with an ejector plate positioned horizontally on the turntable, below lower mold parts to be mounted thereon. A pair of vertical linear actuators positioned at opposite sides of the turntable raise and lower a beam having a central opening. An annular thrust bearing is supported within a vertical cage below the beam s opening. An upper mold part mounting member, rotatable about the bearing retainer cage in position to receive downward thrust from it, has a central opening aligned with those of the beam and the thrust bearing, so that molten metal may be poured through them. The thrust bearing is of the self-aligning type, to hold the upper and lower mating mold parts continuously sealed, at all angular positions of rotation, under the down-thrust of the beam. The turntable has detent means to stop it at a selected angular position. Hook-like hanger members, on the beams undersurface radially outward of the upper mold part mounting member, raise it when the beam is lifted and detain it, as it is raised, in alignment with the angularly detained turntable. When the beam rises to its uppermost limit of movement, a lever mechanism lifts the ejector plate, and upward projections from it, which penetrate the lower mold parts.

Where core parts are to be used, they may mate with the upper and lower permanent mold parts at their radially outer sides, to be withdrawn horizontally outward before a casting is stripped from the lower mold parts.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view partly in elevation and partly in section of a centrifugal casting machine embodying the present invention, with the beam raised. The phantom lines show the beam raised to the top of its stroke, to actuate the ejection mechanism.

FIG. 2 is a plan view thereof.

FIG. 3 is a fragmentary sectional view taken along line 33 of FIG. 1 with radially outer core shoes in position for molding. The phantom lines show the core shoes opened outward.

FIG. 4 is a view similar to FIG. 1 showing the beam lowered to close the mold parts. A removable pouring sleeve and funnel are also shown.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment of centrifugal casting machine, illustrated in the drawings, includes a rigid frame generally designated 10, having a broad base plate 11, a hollow cylindrical pedestal 12 centered thereon, and an elevated horizontal platform 13 extending from the pedestal l2 spacedly above the base plate 11. Within the pedestal 12, mounted within upper and lower bearings 15, 16 at the platform 13 and base plate 10, is a vertical drive shaft 17 onto which a driving sprocket 18 is secured by a collar 19. Conventional power drive means, such as an electric motor, gear reducer, and controls, not shown, drive the shaft 17 through a driving chain 20 at a desired rate of rotation.

Secured onto the upper end of the drive shaft 17 projecting above the platform 13 is a heavy turntable generally designated 23, having a horizontal upper table surface 24, a circular outer edge 25, and an undersurface 26 terminating inwardly in a central mounting portion 27. Means are provided to stop and latch the turntable 23 at a selected angular stopping position. Referring to FIGS. 1 and 4, a vertical bore 28 is drilled upward in the undersurface 26 of the turntable 23 somewhat inwardly of its outer edge 25, to receive the tapering upper end 29 of a latching shaft 30 which extends substantially vertically upward through a bore 31 in a guide bracket 32 mounted onto and laterally from the platform 13. At the lower end of the latching shaft 30, secured by a lateral pivot pin 34 therethrough, is a fitting 35 whose lower end bears downwardly against a compression spring 36 seated on the base plate 11, which urges the shaft 30 upwardly. The pivot pin 34 passes through the inner end of a latching lever 37 whose outer end is mounted by another pivot pin 38 to and angle bracket 39 secured to the base plate 11. At a point intermediate between the lateral pivot pin 34 and pivot pin 38, the lever 37 is bored to'receive an intermediate pin 40 which mounts a clevis fitting 41 secured to the lower end of a latchoperating shaft 42. The shaft 42 passes upward through a bore 43 in a right hand cylinder-mounting plate 63 hereafter described, and terminates spacedly thereabove in a square cut upper end 44. When the end 44 is pressed downwardly, the shaft 42 drives the latching lever 37 downward, against the resistance of the compression spring 36, as shown in phantom lines in FIG. 4, to withdraw the upper end 29 of the latching shaft 30 from the bore 28 and thus permit rotation of the turntable 23.

Secured to the upper surface of the turntable 23 are a plurality of support spacers. As best shown in FIG. 3, these include a pair of inner rectangular spacer blocks 46, located at opposite sides of the axis b of the drive shaft 17, and an alternating pair of segment-shaped outer spacer blocks 47, whose inner edges 48 are parallel to each other and whose outer edges 49 may be arcuate, formed to nearly the same radius as the turntable 23. Onto the upper surfaces of the spacer blocks 46, 47, is secured a lower mold plate 50, bearing a principal lower mold part g, shown in FIG. 1.

Normally resting upon the upper surface 24 of the turntable 23 is a substantially rectangular ejector plate, generally designated 52, whose thickness is substantially less than the thickness of the spacer blocks 46, 47. It has parallel longitudinal side edges 53 which fit slidably within the inner edges 48 of the segment-shaped blocks 47; and it has rectangular windows 54 fitting slidable about the outer edges of the spacer blocks 46. The length of the ejector plate 52 is such that its radially outermost side edge portions 56 project substantially beyond the outer edge 25 of the turntable 23. Mounted onto the ejector plate 22, to extend upwardly and penetrate the plate 50 and the lower mold part 3 are a plurality of ejector pins 57 which serve as stripping projections.

Positioned at the outermost ends of the base plate 11, diametrically opposite each other with respect to the axis b, are a pair of conventional reversible hydraulic linear actuators generally designated 60. Each includes an actuator bottom 61, an outer actuator cylinder 62 secured by a mounting plate 63 to he platform 13, and an actuator shaft 64 terminating in an upper threaded connector end 65 having a beam-mounting nut 66, as shown in FIG. 1.

Bridging between the upper connector ends 65 of the actuators 60 is a heavy beam generally designated 70, which extends across the turntable 23 and over its axis b and is there radially enlarged and bored to provide a central opening 71 aligned with the axis b. Secured across the upper surface of the beam 70 above each actuator 60, with adequate clearance around the beam-mounting nuts 66, is a lateral yoke 72 whose ends 73 extend beyond the side edges of the beam 70 and have vertical bores 74 through which ejector link rods 75 pass with clearance. The upper end 76 of each ejector link rod 75 is threaded and fitted with a pair of nuts 77, one of which serves as a stop nut. The lower ends of each of the rods 76 has a clevis fitting 78, pinned to one of a pair of inward extending levers 79 adjacent to each actuator 60. The levers 79 are pivot-mounted by their outer ends on ejector brackets 80 projecting outward from the platform 13. Bridging across the inner ends 81 of each pair of levers 79 is a narrow lifter plate 82 which in normal position, shown in solid lines in FIG. 1, extends at a slight spacing below the outer edge portions 56 of the ejector plate 52. When the beam 70 is raised by the actuators 60 to a point close to their uppermost limit of movement, the rising yoke ends 73 engage the lower of the nuts 77. The final upward movement of the beam 70 to its uppermost limit, as shown in phantom lines in FIG. 1, causes the ejector link rods 75 to raise the levers 79 and their lifter plates 82 thus are brought upwardly into contact with, and to lift, the outermost side edges 56 of the ejector plate 52.

At one side of the beam 70, shown at the upper right of FIG. 2, is welded an angle bracket 84 drilled and tapped in alignment with the latch-operating shaft 42, to mount a bolt 85 whose head projects downward, and whose position is secured with a stop nut 86. On downward movement of the beam 70 from its FIG. 1 position to its FIG. 4 position, the head of the bolt 85 contacts the upper end 44 of the shaft 42 to depress the latching shaft 30 and release the turntable 23 from the angular position at which it is latched between casting operations.

Secured to the undersurface of the beam 70 is an annularly inward bearing retainer support flange 87, which, under circumstances to be described, suspends a shallow hollow cylindrical bearing retainer generally designated 88. Resting within it on a lower race 89 is an annular thrust bearing generally designated 90. The thrust bearing 90 is of the self-aligning type; its upper race 91 has a spherical upper surface, which fits beneath and within a spherical lower surface of an uppermost thrust communicating bearing portion 92 immediately beneath an annular thrust-applying surface portion 93 of the beam 70, at and outward of its central opening 71. The bearing retainer 88 has a shallow hollow cylindrical wall 94 terminating at its upper margin in an outward extending flange 95 and at its lower margin an inward extending thrust-applying flange 96. The upward flange 95 is received within the bearing retainer support flange 87, to be suspended by it when an upper mold mounting plate generally designated 100 is removed from the wall 94 of the bearing retainer 88 for changing upper mold parts generally designated d, best shown in FIG. 1.

Mounted about the cylindrical wall 94 of the bearing retainer 88, by its circular well portion 98, is an upper mold mounting plate generally designated 100. At the base of the central well portion 98 is a thrust-transmitting flange 99 which annularly surrounds the axis b. In casting, the flange 99 abuts and receives down-thrust from the thrust-applying flange 96 of the bearing retainer 88.

Referring to FIG. 2, the mounting plate 100 as seen in plan view has a pair of larger-radius outer edge portions 101. These are connected by intermediate edge portions 102, illustrated as being straight. Considered functionally, these portions 102 are portions of lesser radial extent than the larger radius portions 101, and they are so referred to in the claims.

As seen in FIG. 1, the bearing retainer 88 and mounting plate 100 position themselves spacedly downward below the beam 70 as it rises, bringing the thrust bearing out of thrust-applying relationship. Its downward spacing from the beam 70 is limited by the contact which the mounting plate larger radius edge portions 101 make with inward projecting hook portions 104 of hanger members 103, secured to the undersurface of the beam 70 radially outward of the axis b. In contrast, when the thrust bearing 90 is in thrust-receiving relationship, as shown in FIG. 4, the mounting plate 100 may rotate within the hanger members 103 spacedly above their hook portions 104.

Thus, when the beam 70 first rises from the FIG. 1 position, it moves out of thrust-applying relationship with the bearing 90; on its further upward movement, the upper mold mounting plate 100 is engaged and raised by the hanger members 103. This engagement also serves to detain the mounting plate 100 in an angular position aligned with that of the latched turntable 23; this alignment is normally retained as the beam 70 rises, to permit a casting to be removed, and until it again returns downward to the FIG. 1 position for pouring another casting.

Such normal angular retention of the mounting plate 100 is easily released to make possible changing the upper mold parts d, hereafter referred to. With the beam 70 lowered in its FIG. 4 position, the latching shaft 30 is depressed and the turntable 23 is turned through an angle which may be somewhat less than 90, the upper mold mounting plate 100 turning with it as shown in phantom lines in FIG. 2, until its large radius portions 101 angularly clear the hanger members 103. Then on raising the beam 100, the upper mold part d and upper mold mounting plate 100 will remain in place on the lower mold part g, from which they may be lifted manually to change the mold parts. As the beam 100 rises, the upper flange of the bearing retainer 88 will engage the bearing retainer support flange 87, which thereafter suspends the bearing retainer 88 from the beam 70.

Considering those hanger members 103 to the left of the axis b as first hanger means and those to the right as second hanger means, it is to be noted that each of these means extends over an are less than 90, and each larger radius edge portion 101 of the mounting plate is of only slightly greater extent, in any event less than the supplement of the angular extent of said first or second hanger means.

In pouring a casting, the molten metal must be poured into the upper and lower mold parts d, g, hereafter described, without damage to the thrust bearing 90 and associated parts. For this purpose, a removable pouring sleeve generally designated 105 is shown in FIG. 4, removed upwardly. In use, its cylindrical sleeve portion 106 is inserted through the beam central opening 71 and the thrust bearing 90 until its horizontal upper flange 107 rests on the upper surface of the beam 70. The lower inner portion of the cylindrical sleeve portion 106 may be made radially smaller, to provide an upward-facing shoulder 108 and truncated conical portion 109 therebeneath, with a non-locking taper of 10 or more.

To introduce the molten metal into the pouring sleeve 105, a pouring funnel generally designated 110 is provided, preferably at the end of an arm 111 attached to the upper surface of the beam 70 by a hinge bracket 112. The hinged end 113 of the arm 111 is offset to rest against the beam 70 when the arm 111 is raised slightly beyond 90", thus to support the pouring funnel 110 nearly vertically. The arm 111 is of such length as, when lowered, to position the funnel 110 at the axis b. At the axis b, it has a radial enlargement 114 including a pouring opening 115, beneath which a funnel-like sleeve 116 is welded. In use, its lower edge 117 abuts the inner edge of the shoulder 108 of the pouring sleeve 115, to guide the molten metal inward into an axial opening f in the upper mold part d.

The configuration of the upper and lower mold parts d, 3 will be dictated, as will be understood, by the requirements of the casting to be made. Any such upper mold part d to be used for centrifugal casting will however have an annularly raised axial pouring opening f, as shown in FIG. 1, tapered to mate with the taper of the conical portion 109 of the pouring sleeve 105, which receives the metal introduced through the funnel 100 and pouring sleeve 105.

One of the exemplary uses of the present centrifugal casting machine is to cast automobile wheels. The upper and lower mold parts d, g, shown somewhat schematically in FIG. 1, are shaped to form the outer and inner surfaces of such a wheel, the solid central portion below the pouring opening f, serving as its hub after removing the gate and machining.

However, to form the drop center rim portion of an automobile wheel, radially outer core parts h are required. In order to utilize core parts h which are permanent, I have devised means, generally designated 120, to affix them in position to mate with the upper and lower mold parts d, g for castings and to draw them outward from such mating position, to permit removal of the casting. These mounting means 120 will now be described.

Referring to the upper part of FIG. 3, there is mounted on the turntable 23, preferably within a vertical bore in the outer spacer block 47 there shown, a vertical hinge pin 121 which establishes a core affixment pivot axis radially outward of the lower mold part 3. Onto the pin 121 are mounted the hinged ends 122 of a pair of core support shoes 123 which are formed in semi-circular arcs; the hinged ends 122 project radially outward from these arcs. Onto the inner surfaces of the core shoes 123 are mounted the rim-forming core parts h, which in this embodiment extend 180 and, as seen in the cross-section shown in FIG. 1, are so shaped as to form the outer drop center portion of the rim of the wheel to be cast.

The semi-circular core shoes 123 have, opposite to their hinged ends 122, means to secure them in a circle concentric with the axis b, and to release them. Referring to FIGS. 1 and 3. such opposite ends are formed to have outwardly facing mating abutments 124, with deep horizontal slots 125 offset vertically from each other. In the mating surfaces of the abutments 124 are mating vertical grooves 126 which meet around a wrenching pin 127 mounted vertically, for angular turning, within a vertical bore 128 in that spacer block 47 opposite to the hinge pin 121. The wrenching pin 127 has, at levels corresponding to those of the horizontal slots 125, upper and lower cylindrical eccentrics 129, 130 offset angularly from each other. Mounted on these eccentric 129, 130 are a pair of latching hooks 131 which extend in opposite directions within the slots 125, to engage latch rods 132 welded vertically across the opposite sides of the abutments 124. Turning the wrenching pin 127 180 will so rotate the offset eccentrics 129, 130 as to extend the hooks 131 sideward and release them from engagement with the rods 132. When so released, the hooks 130 are pivoted in the slots 125; and the core support shoes 123 may then be swung open about hinge pin 121 as shown in phantom lines in FIG. 3, thus moving the core parts h outward in a horizontal plane.

The lower mold part g is formed with bores to fit closely about the ejector pins 57; when it is mounted on the spacer blocks 46, 47 above the ejector plate 52, care is taken to see that the pins 57 may move upward freely when the ejector plate 52 is raised.

The upper mold part d is mounted to the mounting plate 100 in such angular position, verified by an angular index not shown, that the circular outer edge portions 101 of greater angular extent will be engaged by the hanger members 103 when the upper and lower mold parts d, g are in precise alignment and the turntable 23 is latched in angular position by the latching shaft 30. To assure perfect registration of the upper and lower mold parts d, g, mating vertical pins and bores, not shown, are provided. The mounting of the mold parts is accomplished with the beam 70 raised in the FIG. 1 position, and secured by lowering the beam 70.

Utilizing horizontally movable core parts h as shown, these will normally be mounted onto their core support shoes 123 and secured together about the lower mold part g before the upper mold part d is lowered, to check alignment and fit of the mold parts.

Prior to pouring a casting, the pouring sleeve and funnel are inserted into the central opening 71. Through the drive chain 20, the drive mechanism is engaged, to rotate the turntable 23. The downward thrust of the actuator 60 at both ends of the beam 70 holds the mold parts a, g, h sealedly mated, without any other clamping force. This is due to two design factors. First, the fluid pressure exerted by the actuators 60 at both ends of the beam 70 holds it somewhat resiliently downward, to minimize the effect of any slight angular tolerance in alignment. Second, the self-aligning thrust bearing 90 will so adjust itself, throughout the cycle of rotation, as to apply the actuator thrust to hold the upper and lower mold parts d, g in sealed alignment despite tolerances in the assembled machine and mold parts. Consequently, as molten metal is poured and is forced radially outward under centrifugal pressure, it will not escape from between the mold parts d, g, it; nor will rotation disturb their alignment so much as to cause outflow of excessive amounts of flash.

A modification of the present invention, which requires no illustration, may be made if it is desired to employ core parts projecting upward from bores within the lower mold part. In this modification, the plate beneath the lower mold part which, in the embodiment illustrated, serves as an ejector plate, would instead be spring mounted at a position normally above the level of the turntable, and the operating linkage so altered so as to impart a downward reciprocating motion to it when the beam reaches its uppermost position. Then, instead of the stripper pins illustrated, such upward projecting cores may be mounted on the plate, to be stripped downwardly by the altered lever mechanism.

The present construction is adapted to many modifications; for example, other means to hold core parts and move them outward from the center may be substituted to facilitate casting removal. As another example, the hanger members 103 may be so mounted to the beam 70 that their hook portions 104 can be turned angularly to remove them from beneath the edge of the upper mold mounting plate. This modification permits the use of a circular mounting plate.

I claim:

1. A centrifugal casting machine adapted to use permanent molds closing vertically, comprising a lower rotatable turntable having a vertical axis,

means to mount a lower mold part on the turntable,

power means to rotate the turntable,

downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis,

an annular thrust bearing supported at said axis by the beam-like means in position to communicate downward thrust therefrom,

upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing,

powered actuator means selectively to drive the beam-like means downward to thrust-applying position and to raise it upward, and means, responsive to raising the beam-like means from such thrust-applying position and returning it thereto, to respectively disengage the upper mold part mounting means from the thrust bearing and re-engage it thereto,

whereby on downward movement of said beam-like means, prior to its re-engagement with the thrust bearing, an upper mold part mounted onto the said upper mounting means may align itself with a lower mold part mounted onto said lower mounting means.

2. A centrifugal casting machine as defined in claim 1, together with a pouring spout positionable through the axial openings in the beam-like means and thrust bearing.

3. A centrifugal casting machine as defined in claim 1, wherein the annular thrust bearing is of the self-aligning type, whereby to apply the downward thrust from the beam-like means to hold such mating mold parts continuously sealed at all angular positions during rotation despite tolerances in alignment of the machine and mold parts.

4. A centrifugal casting machine as defined in claim 1, wherein the beam-like means extends diametrically across the turntable to opposite beam ends, and

the actuator means comprises two vertically-positioned fluid pressure actuators based adjacent to the turntable opposite to each other and having upper actuator parts secured to the opposite beam ends,

whereby fluid pressure in the actuators will exert such downward force at both ends of the beam-like means, while the turntable is rotating, as to hold such upper and lower mold parts sealed'despite tolerances in alignment.

5. A centrifugal casting machine comprising a lower rotatable turntable having a vertical axis,

means to mount a lower mold part on the turntable,

power means to rotate the turntable,

downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis,

an annular thrust bearing supported at said axis by the beam-like means in position to communicate downward thrust therefrom, upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing, and powered actuator means selectively to drive the beam-like means downward and to raise it upward, together with means, supported by the turntable, to affix radially outer permanent mold core parts in position to mate with such upper and lower permanent mold parts,

said means to affix including means to move such core parts outward from such mating position,

whereby, on outward movement of such core parts and raising of such upper mold part, a casting having a re-entrant portion positioned radially outward may be stripped from such lower permanent mold part.

6. A centrifugal casting machine as defined in claim 5, together with means to establish a vertical core-affixment pivot axis radially outward of such lower mold part,

a pair of core support shoes formed in semi-circular arcs,

hinge means at one end of each of said shoes and positioned outward of its arcuate inner surface to mount the said shoes on such vertical pivot axis, and

latch means to secure the other ends of the core support shoes in an inward position abutting such lower mold part,

whereby, on release of the latch means, the shoes, with such core parts as may be supported by them, may be pivotally moved outward from such lower mold part, thereby to permit a casting to be stripped therefrom.

7. A centrifugal casting machine comprising a lower rotatable turntable having a vertical axis,

means to mount a lower mold part on the turntable,

power means to rotate the turntable,

downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis,

an annular thrust bearing supported at said axis by the beam-like means in position to communicate downward thrust therefrom,

upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing, and

powered actuator means selectively to drive the beam-like means downward and to raise it upward, together with plate means rotatable with the turntable, the plate means being of such dimensions as to leave upper surface portions of the turntable uncovered, and having outer edge portions projecting beyond the turntable, together with mechanism including means to reciprocate the plate means by its said outer edge portions,

whereby, on affixing, onto such uncovered portions, spacer blocks thicker than the plate means and mounting a lower mold part thereupon, the plate means may be reciprocated by its outer edge portions beneath such lower mold parts, to serve as an ejector plate, or, if cores be affixed thereto, a core stripper plate.

8. A centrifugal casting machine as defined in claim 1,

together with wherein the means to lift the ejector plate means includes a lever pivot-mounted adjacent to the power actuator means and having a lifter end extending below the radially outer edge portion of the ejector plate means, and

linkage means to raise the lifter end of said lever when the powered actuator means raises the beam-like means to a position near its uppermost limit of movement.

10. A centrifugal casting machine comprising a lower rotatable turntable having a vertical axis,

means to mount a lower mold part on the turntable,

power means to rotate the turntable,

downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis,

an annular thrust bearing supported at said axis by the beam-like means in position to communicate downward thrust therefrom,

upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing, and

powered actuator means selectively to drive the beam-like means downward and to raise it upward, together with means to stop the turntable at a selected angular stopping position and to release said stop means, responsive respectively to upward and downward movements of said beam-like means.

11. A centrifugal casting machine as defined in claim 10,

together with together with means to permit the beam-like means to move spacedly away from the upper mold part mounting means as the beam-like means commences to raise, and

means carried by the beam-like means to limit such spaced movement, and at the limit thereof, to lift the upper mold part mounting means and to restrain it from rotational movement.

13. A centrifugal casting machine as defined in claim 12,

wherein said means to lift, and prevent rotation of, the upper mold part mounting means comprises hangar means mounted to the beam-like means radially outward of the upper mold part mounting means and having a portion projecting radially inward of the edge of said mounting means spacedly below its position when in thrust-receiving relationship.

14. A centrifugal casting machine as defined in claim 13,

wherein the hanger means includes first and second hanger means supported by and beneath the beam-like means, projecting inward toward the axis and positioned opposite each other,

each said oppositely positioned first and second hanger means extending over an are less than 90, and wherein the outer edge of the upper mold part mounting means includes two portions of larger radial extent, positioned opposite to each other, each having an arcuate angular extent less than the supplement of the arcuate angular extent of one of said first or second hanger means,

said larger radius portions being connected by intermediate portions of lesser radial extent,

whereby, the hanger means permit removal of the upper mold part mounting means by turning its portions of larger radial extent out of angular registration with said first and second hanger means.

15. A centrifugal casting machine as defined in claim 1,

wherein the annular thrust bearing has a hollow bearing retainer member including an inward-extending lower flange and upper retention means, and

the upper mold part mounting means has a well portion into which the outer surface of the bearing retainer is removably received, a central opening therethrough, and means to transmit thrust from the lower flange of the bearing retainer, and wherein the beam-like means has means to suspend the bearing retainer, whereby to hold it when the upper mold part mounting means is removed. 

1. A centrifugal casting machine adapted to use permanent molds closing vertically, comprising a lower rotatable turntable having a vertical axis, means to mount a lower mold part on the turntable, power means to rotate the turntable, downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis, an annular thrust bearing supported at said axis by the beamlike means in position to communicate downward thrust therefrom, upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing, powered actuator means selectively to drive the beam-like means downward to a thrust-applying position and to raise it upward, and means, responsive to raising the beam-like means from such thrust-applying position and returning it thereto, to respectively disengage the upper mold part mounting means from the thrust bearing and re-engage it thereto, whereby on downward movement of said beam-like means, prior to its re-engagement with the thrust bearing, an upper mold part mounted onto the said upper mounting means may align itself with a lower mold part mounted onto said lower mounting means.
 2. A centrifugal casting machine as defined in claim 1, together with a pouring spout positionable through the axial openings in the beam-like means and thrust bearing.
 3. A centrifugal casting machine as defined in claim 1, wherein the annular thrust bearing is of the self-aligning type, whereby to apply the downward thrust from the beam-like means to hold such mating mold parts continuously sealed at all angular positions during rotation despite tolerances in alignment of the machine and mold parts.
 4. A centrifugal casting machine as defined in claim 1, wherein the beam-like means extends diametrically across the turntable to opposite beam ends, and the actuator means comprises two vertically-positioned fluid pressure actuators based adjacent to the turntable opposite to each other and having upper actuator parts secured to the opposite beam ends, whereby fluid pressure in the actuators will exert such downward force at both ends of the beam-like means, while the turntable is rotating, as to hold such upper and lower mold parts sealed despite tolerances iN alignment.
 5. A centrifugal casting machine comprising a lower rotatable turntable having a vertical axis, means to mount a lower mold part on the turntable, power means to rotate the turntable, downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis, an annular thrust bearing supported at said axis by the beam-like means in position to communicate downward thrust therefrom, upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing, and powered actuator means selectively to drive the beam-like means downward and to raise it upward, together with means, supported by the turntable, to affix radially outer permanent mold core parts in position to mate with such upper and lower permanent mold parts, said means to affix including means to move such core parts outward from such mating position, whereby, on outward movement of such core parts and raising of such upper mold part, a casting having a re-entrant portion positioned radially outward may be stripped from such lower permanent mold part.
 6. A centrifugal casting machine as defined in claim 5, together with means to establish a vertical core-affixment pivot axis radially outward of such lower mold part, a pair of core support shoes formed in semi-circular arcs, hinge means at one end of each of said shoes and positioned outward of its arcuate inner surface to mount the said shoes on such vertical pivot axis, and latch means to secure the other ends of the core support shoes in an inward position abutting such lower mold part, whereby, on release of the latch means, the shoes, with such core parts as may be supported by them, may be pivotally moved outward from such lower mold part, thereby to permit a casting to be stripped therefrom.
 7. A centrifugal casting machine comprising a lower rotatable turntable having a vertical axis, means to mount a lower mold part on the turntable, power means to rotate the turntable, downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis, an annular thrust bearing supported at said axis by the beam-like means in position to communicate downward thrust therefrom, upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing, and powered actuator means selectively to drive the beam-like means downward and to raise it upward, together with plate means rotatable with the turntable, the plate means being of such dimensions as to leave upper surface portions of the turntable uncovered, and having outer edge portions projecting beyond the turntable, together with mechanism including means to reciprocate the plate means by its said outer edge portions, whereby, on affixing, onto such uncovered portions, spacer blocks thicker than the plate means and mounting a lower mold part thereupon, the plate means may be reciprocated by its outer edge portions beneath such lower mold parts, to serve as an ejector plate, or, if cores be affixed thereto, a core stripper plate.
 8. A centrifugal casting machine as defined in claim 1, together with means on the turntable to support such lower mold part at a fixed spacing above the level of the turntable, ejector plate means adjacent to said means to support, and positioned within and being of lesser thickness than such spacing, and rotatable with the turntable, and having upward-extending stripping projections, said ejector plate means having a radially outer edge portion, and ejector mechanism including means to lift the ejector plate means By said outer edge portion.
 9. A centrifugal casting machine as defined in claim 7, wherein the means to lift the ejector plate means includes a lever pivot-mounted adjacent to the power actuator means and having a lifter end extending below the radially outer edge portion of the ejector plate means, and linkage means to raise the lifter end of said lever when the powered actuator means raises the beam-like means to a position near its uppermost limit of movement.
 10. A centrifugal casting machine comprising a lower rotatable turntable having a vertical axis, means to mount a lower mold part on the turntable, power means to rotate the turntable, downward thrust-applying beam-like means extending spacedly over the turntable and having an opening aligned with said axis, an annular thrust bearing supported at said axis by the beam-like means in position to communicate downward thrust therefrom, upper mold part mounting means rotatable about the bearing in position to receive downward thrust therefrom, said mold part mounting means having a central opening aligned with those of the beam-like means and the annular thrust bearing, and powered actuator means selectively to drive the beam-like means downward and to raise it upward, together with means to stop the turntable at a selected angular stopping position and to release said stop means, responsive respectively to upward and downward movements of said beam-like means.
 11. A centrifugal casting machine as defined in claim 10, together with means to stop the turntable at a selected angular stopping position, and means to prevent rotation of the upper mold part mounting means and to detain it in alignment with such angular position when the beam-like means is raised away from the turntable, and to release it for rotation when the beam-like means is returned to lowermost position.
 12. A centrifugal casting machine as defined in claim 10, together with means to permit the beam-like means to move spacedly away from the upper mold part mounting means as the beam-like means commences to raise, and means carried by the beam-like means to limit such spaced movement, and at the limit thereof, to lift the upper mold part mounting means and to restrain it from rotational movement.
 13. A centrifugal casting machine as defined in claim 12, wherein said means to lift, and prevent rotation of, the upper mold part mounting means comprises hangar means mounted to the beam-like means radially outward of the upper mold part mounting means and having a portion projecting radially inward of the edge of said mounting means spacedly below its position when in thrust-receiving relationship.
 14. A centrifugal casting machine as defined in claim 13, wherein the hanger means includes first and second hanger means supported by and beneath the beam-like means, projecting inward toward the axis and positioned opposite each other, each said oppositely positioned first and second hanger means extending over an arc less than 90*, and wherein the outer edge of the upper mold part mounting means includes two portions of larger radial extent, positioned opposite to each other, each having an arcuate angular extent less than the supplement of the arcuate angular extent of one of said first or second hanger means, said larger radius portions being connected by intermediate portions of lesser radial extent, whereby, the hanger means permit removal of the upper mold part mounting means by turning its portions of larger radial extent out of angular registration with said first and second hanger means.
 15. A centrifugal casting machine as defined in claim 1, wherein the annular thrust bearing has a hollow bearing retainer member including an inward-extending lower flange and upper retention means, and the upper mold part mounting means has a well portion into which the outer surface of the bearing retainer is removably receiVed, a central opening therethrough, and means to transmit thrust from the lower flange of the bearing retainer, and wherein the beam-like means has means to suspend the bearing retainer, whereby to hold it when the upper mold part mounting means is removed. 